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<h1 class="topictitle1">An Error Message Indicating new_collation_enabled Mismatch Is Displayed During Restoration</h1>
<div><div class="section"><h4 class="sectiontitle">Precautions</h4><ul><li>The <strong>new_collation_enabled</strong> configuration item takes effect only when the cluster is initialized. After the cluster is initialized, you cannot enable or disable the new collation framework by modifying the configuration item.</li><li>If the upstream and downstream clusters have different values for <strong>new_collation_enabled</strong> and forcible restoration is performed, Backup &amp; Restore (BR) will report a data verification error.</li></ul>
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<div class="section"><h4 class="sectiontitle">Symptom</h4><p>An error message indicating <strong>new_collation_enabled</strong> mismatch is displayed during restoration.</p>
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<div class="section"><h4 class="sectiontitle">Possible Causes</h4><p>In TiDB v6.0.0 and later versions, the default value of <strong>new_collations_enabled_on_first_bootstrap</strong> is changed from <strong>false</strong> to <strong>true</strong>. BR backs up the <strong>new_collation_enabled</strong> configuration item in the <strong>mysql.tidb</strong> table of the upstream cluster. BR securely restores the backup data of the upstream cluster to the downstream cluster only when the upstream and downstream clusters have the same configuration for this configuration item. If the configuration on the upstream cluster is different from that on the downstream cluster, BR will reject the restoration and reports the mismatch error.</p>
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<div class="section"><h4 class="sectiontitle">Troubleshooting</h4><ol><li><span>Connect to the upstream TiDB database instance using the TiDB client tool.</span></li><li><span>Run the following command to check the <strong>new_collation_enabled</strong> configuration item of the upstream cluster:</span><p><pre class="screen">SELECT * FROM mysql.tidb WHERE VARIABLE_NAME = 'new_collation_enabled':</pre>
<p>The following is an example of the command output:</p>
<p><span><img src="en-us_image_0000002164664442.png"></span></p>
</p></li><li><span>Connect to the downstream TiDB database instance using the TiDB client tool.</span></li><li><span>Run the following command to check the <strong>new_collation_enabled</strong> configuration item of the downstream cluster:</span><p><pre class="screen">SELECT * FROM mysql.tidb WHERE VARIABLE_NAME = 'new_collation_enabled':</pre>
</p></li></ol>
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